Criteria for Valve Location and System Reliability

Due to the lack of availability of proper tools for management of valves, it is very difficult for water utilities to supply water with minimum interruption in case of a water main break. Rules or guidelines for the placement of valves in the distribution system are not well defined, and the impact of valve placement rules on system reliability (i.e., minimizing out-of-service customers) has not been quantified in previous studies. The objectives of this research were to develop a rationale for valve location using design rules to optimize system reliability, to develop an easy to use program to analyze the efficiency of valves on the reliability of isolation of distribution networks, and to develop a computer model to analyze complicated networks and assist water utilities in minimizing interruption of supply in isolating water main breaks. The study provides analysis tools and rules for valve placement to allow water utilities to improve system reliability by reducing the number of customers affected by necessary water main isolations. The analysis tools can be used to identify critical valves and provide a quantitative basis for making cost-effective decisions about valve placement. The report includes a CD-ROM that contains the Strategic Valve Management Model (SVMM). The SVMM was developed to provide utilities with a better tool for valve maintenance and system expansion. The program is used to identify segments in water distribution systems and to simulate pipe and valve failure effects on the system.